how do i get rid of these weird black lines on my links bar?

so, there are these ugly little lines that appear after each link on my nav links.

i did some inspect elementing and figured out it's this weird thing called ::after. i'm still confused on what the hell this is but eventually i found out if i just set the content to "none" it would go away, and it did. but only in the inspect element view.

when i pasted the fixed code into my profile html, it did nothing. i'm not the brightest when it comes to html/css so i dunno what i did wrong. anyone know how to fix this?

have you tried using display:none instead? that works for my friends n i